Core barrel



May 16, 1933. J. N. oKsr-:NHOLT GORE BARREL Filed Nov. 12, 1929 Patented May 1.6, 1933 4UNITED STATES PATENT OFFICE JENS N. OKSENHOLT, F IBOYCE, LOUISIANA, ASSIGNOR 0F ONE-EIGHTH T0 MIS CHRISTINE JEFFBIES, OF SAN ANTONIO, TEXAS `conn BARREL Application med November 12, 1929. Serial No. 406,617.

The invention relates to certain yimprovements in rotary well drilling apparatus, more particularly to a novel form of core barrel adapted to be applied to and removed from operative relation within the drill stem and bit without removing the drilling string from the bore hole'. To this end, the invention comprises a tubular core barrel having a lower cutting edge or rim and oppositely 'lo disposed lugs on its outer surface adapted to cooperate with guiding and locking lugs on the inner wall of the drill stem, so that the -core barrel may be lowered or dropped into the drill stem from the top thereof until it is arrested by the bit on the end of the core barrel or by the locking and guiding lugs, when the relative rotation between the drill stem and the core barrel and lowering of the drill stem will move the lugs onthe core barrel into locking engagement with the lugs on the interior of the drill stem.

The invention is illustrated in the accompanyin g drawing, in which Fig. 1 is a sectional elevation of the lower portion of the drill stem and bit, with the core barrel shown in locked relation therein.

Fig. 2 is a similar view taken at right angles to that shown in Fig. 1.

Fig. 3 is a horizontal section on line 3-3 3o of Fig. l.

Fig. 4 is a corresponding section on line 4-4 of Fig. 1. A

Referring to the drawing, 1 indicates the drill stem which is usually made up of jointed sections of pipe or tubing, to the lower end of which is connected the bit 2, which, in the form illustrated, is of the reamer type having cutting blades 4, 4 projecting from its outer surface, the lower end of the bit being of less diameter than the drill stem and having an opening therein substantially equal to the outer diameter of the core barrel to be herein; after described.

The core barrel 5 comprises a section of tubing of the desired length, usually five or six feet, and having an internal diameter slightly larger at the top than at the bottom, in order to facilitate the removal of the core from the interior of the barrel. The lower 5 end of the core barrel is provided with a cut- .core barrel.

ting edge, exemplied as`6, 6, and is also provided with several longitudinal grooves 6 to permit the usual lubricating water to pass the Secured at opposite points to the i outer surface of the core barrel are lugs 7, 7 55. which cooperate with guiding and. locking lugs on the inner wall of the drill stem, either to hold the core barrel in operative relation within the drill stem and bit, as shown, or

to release the core barrel and permit the latter to be withdrawn from the drill stem without removing the drilling apparatus from the well bore. The upper end of the core barrel is fitted with an outwardly opening check valve of the usual type employed in this form 55 of apparatus, which serves t0 permit material to be forced out of the top of the core barrel and to prevent the entrance of water or other material into the top of the core barrel.

The locking means formed on the inner walls of the drill stem comprises guiding and locking lugs disposed opposite to each other and which may be .formed either integrally with the lower section of the drill stem or may be cut from sheet steel bent to proper contour and secured to the inner Wall of the drill stem section by riveting, spot welding or other suitable means. Each of said lugs comprises a head section, including two convexly curved sides or edges 8 and 9 which 80 converge or intersect at the tip of the lug, the side or edge 9 terminating in a hook-like shoulder 10, which is followed by an inner seat 11 against which one ofthe lugs 7 on the core barrel is designed to seat. Below the seat 11, the side or edge of the lug is curved, as at 12, and terminates in a semiannular base section 13. The opposite edge of the lug is straight, as at 14, the two straight e ges 14 of the corres onding lugs 99 serving as guides for thev lugs g on the core barrel as the latter is being applied to or removed from the drill stem. As shown, the

straight edge 14 of each lug lies adjacent or opposite the inwardly curved edge 12 of the 95 companion lug and the hooked ends 10 project i-n the same direction circumferentially.

To apply the core barrel to its operative relation within the drill stem and bit, the drill stem is raised a short distance, sol that the 10 terior drill stem until the sai bit will clear the bottom of the drill hole the core barrel is then dropped or lowered through the drill stem and, when the lugs A7, 7 on the core barrel encounter either inclined faces 8 or 9 Aon the guiding and locking lugs, the core barrel will be rotated, so that the lugs 7 will enga e and slide along the straight edges 14 oft e lu s on the inlugs 7 encounter the base sections 13 of the guide lugs and the core barrel is arrested with its end projecting beyond the' lower face of the bit 3.

ing penetrated by the apparatus, which speci-- men will be retained within the core barrel, as will be understood by those skilled in the art. After the core has been cut and it is desired to inspect the same, the corev barrel may be readily removed 0r withdrawn from the drill stem Without removing the latter from the drill hole, the withdrawing operation involving a slight raising of the drill stem, which will cause the lugs 7 on-the core barrel to ride down the curved edges 12 of the locking lugs until said lugs 7 engage the straight vertical edges 14 of the locking lugs, so that, when the core barrel is then engaged by a suitable fishing device, such as commonly employed in well drilling apparatus, it may be pulled upward directly out of engagement with the locking lugs and then withdrawn through the length of the drill stem to the surface.

It will be understood that the specific type of bit and its mode of association with the drill stem are purely exemplary and that the invention is applicable 'to any of the standard types of drill stems and cutting bits, such as commonly employed in association with core barrels. The inherent novelty and utility of the present invention, however, resides in the provision of the core barrel, which may be applied to or removed from operative position in the drill stem and bit without withdrawing the drill stem from the well, the means for locking and unlocking the' core barrel with respect to the drill stem being in the nature of a slip or bayonet joint connection between the core barrel and the drill stem, which connection preferably takes the form of the oppositely disposed guiding and locking lugs on the inner face of the drill stem and bit, and cooperating ra dial lugs on the core barrel.

What I claim in:

1. In combination with a rotary drill bit and stem, of a core barrel and a slip joint connection consisting of fixed interengaging the latter are in working relation in the drill hole.-

2. In combination with a rotary drill bit and stem, of a core barrel and bayonet joint connection between the interior of the stem and the exterior of the barrel, whereby the barrel may be applied to and removed from operative relation with the stem and bit while tlhf latter are in working relation in the drill 3. In combinationwith a rotary drill bit and stern, of a core barrel and a double bayonet joint connection between theinterior of the stem and the exterior of the barrel, whereby the barrel may be applied to and removed from operative relation with the-stem and bit while the latter are in working relation in the drill hole. A

4. The combination of a rotary drill bit and stem, of a core barrel, and means for detachably securing the barrelwithin the stem and bit, said means comprising oppositely disposed fxed uiding and locking lugs on the inner wall o? the stem, and fixed radial lugs Y on 'opposite sides of the core barrel.

5. The combination of a rotary drill bit and stem, of a core barrel, and means for detachably securing the barrel within the stem and bit, said means comprising oppositely disposed guiding and locking lugs on the inner wall of the stem, and -radial lugs on opposite sides of the core barrel, each lug on the stem including a substantially semicylindrical base, a straight edged side and an inwardly curved edged side terminating in a hook-like shoulder, and a head section having intersecting convexly curved side edges, the straight side of each lug facing the curved side of the other.

In testimony whereof, I affix mysignature.

JENS N. OKSENHOLT. 

